LCY every time if I'm close to it. I think you get a voucher to spend in one of the restaurants in lieu of lounge, it's a far nicer experience anyway because it's a quieter and much more civilised airport. The club lounges at Heathrow aren't all that good anyway and for a short flight I'd be fine with no free middle. I think seat 2D (front aisle right hand side) is great for legroom on the small aircraft.

If there are weather issues you'd be transferred to LHR and this is straightforward.

I would personally go in economy if I were paying myself and didn't need TPs, the experience is quite similar and you just need to add a checked bag.

EDIT - withdrawing the suggestion of a food voucher as I think this was a recollection of using a non-Amex PP.